Refurbishing & Polishing Split Rim Lips

• Things you’ll need:
  • A small file
  • Wet & dry paper of varying grades
  • Polish/polishing equipment

• The first thing to do is assess the damage. Even though the same approach will be taken, you need to have a plan before picking up a file. If the damage is light, you should be able to make the area as good as invisible, but if it’s deeper – either accept the fact that it’s never going to be fully removed (safer option), or risk filing out a noticeable section of the lip. When you file the lip, you are not only removing material, but reshaping it. This is in both the profile (i.e. roundness), and also the flatness of the repair. The aim of the game here is to maintain a profile that matches the rest of the wheel, while ensuring that you never file too much away from one area that it becomes noticeable. This is why it is sometimes necessary to file beyond the damaged part of the wheel; effectively blending in the lowest point of the lip with the surrounding, undamaged metal.
  
  
• Depending on the design of the lip, a small, flat file is usually best as it can be used precisely and with control. You can quite quickly remove damaged metal by rubbing in one spot, but by filing over the top of the lip – following the rounded profile – it’s quite easy to reshape the area, too. There’s not much else to say about filing except to keep checking your work and viewing it from different angles. If you’re worried you’ve taken too much out, stop and reassess the area. It’s easy to file metal away, but you can’t put it back in. However if when you’ve removed the damage you can see a low spot, don’t be too scared about filing away part of the surrounding lip to disguise it. This is an important step if you want to achieve a great finish, just don’t get too carried away or you’ll end up with no wheel left…
  
  
• After you’ve got the damage out and you’re happy with the shape of the lip, it’s time to move on to sanding. Don’t seek perfection with the file, its job really is to remove the heaviest damage and you can always file some more if you need to. The next step – which becomes a recurring theme in this guide – is to remove the marks left by the previous step. In this case grab some sand paper (try 320 grit for starters) and smooth out the area which has just been filed. You’ll find different ways to pinch and fold the sandpaper to get the best out of it, and hopefully end up with a result that gives your wheel its final, refurbished shape (prior to more sanding and polishing).

• Sanding
  • By far the most important and time consuming part of the polishing stage is actually more sanding. For wheels in the condition shown, a rotary tool is indispensable. These can be purchased cheaply and will save many hours of sanding by hand, just make sure the tool you use has a flexible attachment for the harder to reach areas.  The purpose of the rotary tool is to remove pitting and/or corrosion from the surface of the metal, but this will still need to be followed up by many stages of wet & dry by hand until the surface is smooth enough to polish.
  • The theory behind polishing is simple: remove imperfections with a rotary tool/wet & dry paper before moving through finer grades to take out the scratches left by the previous stage. Eventually (1200 grit minimum) the metal surface will start to catch a reflection and this is the earliest time you should consider starting to polish. The finish will be further improved if you go beyond this to even finer grits, after which the final polishing should then be carried out by a machine polisher (or converted bench grinder) for the best possible finish.
  • Required tools:
    • Rotary tool with flexible attachment.
    • Flap wheels (240 grit).
    • Wet and dry paper (320 – 1200+ grit).
    • Bench polisher with cotton mops and polishing compounds.
  • Start by using a rotary tool to remove the worst pitting and corrosion. The best attachment we have found for this is a miniature flap wheel in 240 grit. These are available on eBay and a pack of 20 will be more than enough to do a set of 4 split rim lips. The beauty of flap wheels is that they strike the suface of the metal in a slightly different place with each rotation; making them very safe to use. They can get into reasonably tight spaces and their level of abrasiveness does not change as the extremities of each “flap” wears away (yet different speeds can be used). The aim here is to remove as many imperfections as possible, as those remaining from any stage of sanding will still be visible when the metal is finally polished. Do however exercise caution and use common sense – some pitting may simply be too severe to remove in its entirety.

• Wet Sanding
  • After the worst of the pitting has been removed, wet and dry paper is used to take out the scratches left by the previous sanding stage. 320 grit is a good starting point after using the rotary tool but you can experiment with finer or coarser grades. When you’ve found the correct grade, keep sanding until the finish is entirely uniform and the only marks remaining are from the wet and dry paper itself (this rule is true throughout the entire process). Be sure to keep the wet and dry paper lubricated with plenty of soapy water and don’t ever go any lower than 240 grit. If the metal was already in good condition and you skipped the rotary tool stage, we’d recommend starting at around 400 grit.
  • Continue sanding through each grade of wet & dry paper, i.e. 400, 600, 800, 1000 and finishing with a minimum of 1200 grit.
  • When you get up to 800 – 1000 grit wet and dry, you should be able to catch a reflection at some angles. It’s up to you when you stop, but if you keep on going to 1200 or beyond the final outcome will be even better. You must not polish the lip before the metal catches a reflection as the surface of the metal is not ready yet. Perseverance here is key.
  • When you finally have a wheel that’s ready for polishing, it should catch a reflection.

• Machine Polishing
  • The only real option for obtaining a high quality finish is with a dedicated polisher or converted bench grinded. Drills with polishing mop attachments are generally a waste of time (unless you need to reach difficult areas) and a full polishing kit can be purchased for well under £100. The theory for polishing is the same as sanding but on a much finer scale. We began with a sewn cotton 6″ mop and Menzerna blue compound to bring the metal to a shine, before finishing it on the loose cotton mop with Menzerna pink compound. Polishing is not difficult but beginners do tend to use too much compound. If too much compound is used, a residue will be left on the metal although this can easily be removed with vienna lime powder.

• Polishing By Hand
  • When you’ve got the metal as shiny as you can, it’s time to do a final hand polish for the ultimate finish. For this you won’t go far wrong with Mother’s Mag and Alu polish and a cotton stockinette. After the final polish be sure to fully protect your wheels before rebuilding them to preserve your efforts.
  • Never use regular Autosol or similarly abrasive polishes on mirror polished wheels as they will inflict fine scratches. Always use the most gentle products possible, but use them often to maintain the shine you have achieved.